Abstract
An extremely strong magnetic field (as strong as 1015 T) is created in the off-central heavy-ion collisions by the spectator protons which "miss" the collisions, flying past each other rather than colliding. The magnetic field is interesting to be studied as it is expected to leave distinct imprints in the distribution of final state charged particles. In addition, novel QCD phenomena are anticipated to emerge with the presence of a strong magnetic field and the formation of charge-parity violating domains inside the medium produced in heavy-ion collisions. The aim of this article is to review two methods utilised by the experimental searches to probe the early magnetic field: the directed flow of charged hadrons (and heavy-flavour hadrons D0 and ¯D0) and the global polarisation of Λ and ¯Λ hyperons. Furthermore, this article is also dedicated to review the searches for one of the novel QCD phenomena, the chiral magnetic effect, at the LHC and RHIC.